© 2005 Pearson Education Inc., publishing as Addison-Wesley
Why does the cloud spin?
Its part of a spinning galaxy—lots of angular
Particles closer to the center of galaxy move more
rapily than particles farther away..speed decreases
with radial distance.
As a shock wave and then gravity compress the
cloud, angular momentum must be conserved, so
toques transfer some angular momentum from the
galactic disk to the interstellar cloud.
This is similar to the formation of cyclones and
hurricanes in our atmosphere.